1. Field of the Invention
The present invention relates to an ink jet printer, and, more particularly, to a low force ink jet printhead capping system for an ink jet printer.
2. Description of the Related Art
Ink jet printers form an image on a print medium by selectively ejecting ink from one or more of a plurality of ink jet nozzles formed in a nozzle plate of an ink jet printhead. In order to maintain the printhead at an acceptable level of performance, ink jet printers typically include a maintenance station for performing scheduled maintenance operations and for providing a sealed environment for the printhead nozzle plate during periods of non-use.
One example of a maintenance station includes a movable maintenance sled including a printhead wiper and a printhead cap. The printhead wiper includes a blade edge for engaging the printhead nozzle plate to remove waste ink and contaminants that have accumulated on the printhead nozzle plate during printing. The cap may used to provide a sealed environment around the ink jet nozzles.
The cap is typically formed as a generally rectangular structure defined by four adjoining walls that extend vertically upwardly from a base, and is made from an elastomer. Commonly, the elastomer cap is placed over the nozzle plate of the printhead to ensure a sufficiently humid environment to avoid undesirable dried ink formation that may plug ink jet nozzles. Such a cap forms a leak-free seal between the printhead nozzles and the ambient environment. Conventionally, this has been done in one of two ways: by forcing the elastomer cap into the printhead with enough force to deform the cap around its sealing lip, or by providing a spring-loaded gimbaling mechanism behind the cap to allow the lip of the cap to xe2x80x9cfloatxe2x80x9d with the printhead. The former typically requires large forces to produce sufficient deformation to ensure a reliable seal, due to manufacturing tolerances. The latter typically requires less force, but adds a significant number of parts, thus increasing the cost and complexity of the cap mechanism.
As ink jet printing technology has evolved, the size of the ink jet printheads has been decreasing, while the size of the nozzle plate and the number of ink jet nozzles in the nozzle plate has increased. As a result, the surface area on the printhead available for establishing an effective seal with the cap has diminished. Also, with the larger-sized nozzle plates and the advent of non-planar printhead topography in the regions surrounding the nozzle plate, the amount of capping force exerted by the maintenance sled has had to increase to effect the same degree of sealing.
What is needed in the art is a printhead capping system that can reduce the amount of capping force required to establish and maintain an effective seal around the printhead nozzle plate.
The present invention provides a printhead capping system that can reduce the amount of capping force required to establish and maintain an effective seal around the printhead nozzle plate.
The invention comprises, in one form thereof, a printhead capping system including a printhead cap having a plurality of adjoining walls. The plurality of adjoining walls has a proximal end and a distal end. The plurality of adjoining walls defines an interior region. A lip portion is provided having a perimetrical sealing surface. The lip portion extends from the distal end of the plurality of adjoining walls in a cantilever manner in a direction non-orthogonal to an extent of the plurality of adjoining walls. In cross-section the lip portion tapers in a direction from the distal end toward the perimetrical sealing surface.
One advantage of the capping system of the present invention is that the printhead cap includes a high compliance sealing lip, which thereby lowers the capping force required to obtain an adequate seal between the printhead and the printhead cap.